Unless otherwise stated, all gemstones are graded and are evaluated in their mountings. Approximate weights and average quality grades are arrived at using the Gemological Institute of America (GIA) grading scale. Mountings prohibit full and accurate observation of gem quality and weight, all data pertaining to mounted gems can be considered as approximate unless accompanied by an independent laboratory report (GIA, AGL or EGL). Major diamonds are graded with the use of pre-graded permanent master diamonds color comparison stones and the grading nomenclature prescribed by the GIA. Colored Gemstones are graded using the GIA prescribed colored stones grading system and nomenclature. Major colored stones are described using Gem Dialogue color grading system.
Authenticity, antiquity, decorative periods, vintages and or circa dating are determined to the best of our ability based on materials incorporated, methods of manufacture, design, hallmarks and signatures, lapidary techniques, technological developments and consultation of our extensive reference library and materials. Dating and period attributions are not an exact science as decorative periods frequently overlap and borrow influences from one another.